Tube unit of ignition spark plug for engine

Abstract

A tube unit of a spark plug for an engine that is used for mounting the spark plug in a cylinder head, may include a spark plug tube including a hollow tube body inserted in an interior mounting hole of the cylinder head, wherein a lower end of the hollow tube body that a gasket is coupled thereto is mounted at an upper end of a penetration hole formed at a lower deck, and a compression bolt engaged to the interior mounting hole of the cylinder head at an upper end of the hollow tube body so as to apply compression force to the hollow tube body and generate surface pressure to the gasket for sealing a gap disposed between the hollow tube body and the penetration hole while the compression bolt is engaged to the interior mounting hole of the cylinder head.

1. A tube unit of a spark plug for an engine that is used for mounting the spark plug in a cylinder head, comprising:
 a spark plug tube including a hollow tube body inserted in an interior mounting hole of the cylinder head, the hollow tube including a sealed lower end having a gasket for sealing against an upper end of a penetration hole formed at a lower deck, wherein the spark plug is slidably received in the spark plug tube and a lower end portion of the spark plug protrudes from the sealed lower end and engaged to the penetration hole; and 
 a compression bolt engaging the interior mounting hole of the cylinder head at an upper end of the hollow tube body so as to apply compression force to the hollow tube body and generate surface pressure against the gasket to seal a gap disposed between the hollow tube body and the penetration hole while the compression bolt is engaged to the interior mounting hole of the cylinder head. 
 
     
     
       2. The tube unit of a spark plug of  claim 1 , wherein the hollow tube body has a reversed-truncated-cone shape. 
     
     
       3. The tube unit of a spark plug of  claim 1 , wherein the hollow tube body is cylindrical. 
     
     
       4. The tube unit of a spark plug of  claim 1 , wherein the penetration hole formed at the lower deck is provided with a thread formed at an interior circumference thereof such that the spark plug is selectively engaged thereto. 
     
     
       5. The tube unit of a spark plug of  claim 1 , wherein the hollow tube body includes an inner slanted surface formed along inner circumference thereof and inclined downwards with a predetermined angle to guide the spark plug to the penetration hole. 
     
     
       6. The tube unit of a spark plug of  claim 1 , wherein the hollow tube body at exterior circumference thereof includes an o-ring mounting hole for mounting an o-ring. 
     
     
       7. The tube unit of a spark plug of  claim 6 , wherein the o-ring mounting hole is formed at an upper portion of the hollow tube body. 
     
     
       8. The tube unit of a spark plug of  claim 1 , wherein the hollow tube body includes a stepped surface formed along exterior circumference at the lower end of the hollow tube body and abutting the upper end of the penetration hole, wherein the gasket is disposed between the stepped surface and the upper end of the penetration hole while the compression bolt is engaged to the interior mounting hole of the cylinder head. 
     
     
       9. The tube unit of a spark plug of  claim 8 , wherein the hollow tube body comprises a mounting groove along the exterior circumference in the lower end thereof under the stepped surface to receive inner circumference of the gasket therein. 
     
     
       10. The tube unit of a spark plug of  claim 8 , wherein an exterior diameter of the stepped surface is smaller than that of the hollow tube body. 
     
     
       11. The tube unit of a spark plug of  claim 1 , wherein at least an outer slanted surface are formed along exterior circumference at a lower portion of the hollow tube body, configured to correspond to the lower deck, and disposed apart from each other by a predetermined distance in a longitudinal direction of the spark plug tube. 
     
     
       12. The tube unit of a spark plug of  claim 11 , wherein the outer slanted surfaces are inclined downwards by a predetermined angle, and an exterior diameter of the outer slanted surface disposed in upper direction is larger than that of the outer slanted surface disposed in lower direction. 
     
     
       13. The tube unit of a spark plug of  claim 1 , wherein the lower end of the hollow tube body is elastic sufficiently enough to be expanded by the compression bolt while the compression bolt is engaged to the interior mounting hole of the cylinder head in a state in which the gasket is inserted therein so as to prevent the gasket from releasing therefrom. 
     
     
       14. The tube unit of a spark plug of  claim 1 , wherein the compression bolt is hollow-shaped and inner diameter of the compression bolt is smaller than outer diameter of the upper end of the hollow tube body. 
     
     
       15. The tube unit of a spark plug of  claim 1 , wherein an upper portion of the compression bolt has a coupling portion in order that the compression bolt can be engaged to or disengaged from the interior mounting hole by an engaging tool. 
     
     
       16. The tube unit of a spark plug of  claim 1 , wherein a screw thread is formed along exterior circumference at upper end of the compression bolt such that the compression bolt is threaded to the interior mounting hole of the cylinder head. 
     
     
       17. The tube unit of a spark plug of  claim 1 , wherein the gasket has an annular shape so as to be inserted in the lower end of the hollow tube body. 
     
     
       18. The tube unit of a spark plug of  claim 1 , wherein the gasket is made of copper material. 
     
     
       19. An engine comprising the tube unit of a spark plug of  claim 1  mounted in a cylinder head. 
     
     
       20. A passenger vehicle comprising the engine  claim 19 .